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Commit 6f44d033 authored by Konrad Rzeszutek Wilk's avatar Konrad Rzeszutek Wilk Committed by H. Peter Anvin
Browse files

x86, doc: Adding comments about .iommu_table and its neighbors. 



Updating the linker section with comments about .iommu_table and
some other ones that I know of.

CC: Sam Ravnborg <sam@ravnborg.org>
CC: H. Peter Anvin <hpa@zytor.com>
CC: Fujita Tomonori <fujita.tomonori@lab.ntt.co.jp>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@redhat.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
LKML-Reference: <1282933173-19960-1-git-send-email-konrad.wilk@oracle.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent ee1f284f

arch/x86/kernel/vmlinux.lds.S

+22 −0
Original line number Diff line number Diff line
@@ -242,6 +242,12 @@ SECTIONS 
		__x86_cpu_dev_end = .;

	}



	/*

	 * start address and size of operations which during runtime

	 * can be patched with virtualization friendly instructions or

	 * baremetal native ones. Think page table operations.

	 * Details in paravirt_types.h

	 */

	. = ALIGN(8);

	.parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) {

		__parainstructions = .;
@@ -249,6 +255,11 @@ SECTIONS 
		__parainstructions_end = .;

	}



	/*

	 * struct alt_inst entries. From the header (alternative.h):

	 * "Alternative instructions for different CPU types or capabilities"

	 * Think locking instructions on spinlocks.

	 */

	. = ALIGN(8);

	.altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) {

		__alt_instructions = .;
@@ -256,10 +267,21 @@ SECTIONS 
		__alt_instructions_end = .;

	}



	/*

	 * And here are the replacement instructions. The linker sticks

	 * them as binary blobs. The .altinstructions has enough data to

	 * get the address and the length of them to patch the kernel safely.

	 */

	.altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) {

		*(.altinstr_replacement)

	}



	/*

	 * struct iommu_table_entry entries are injected in this section.

	 * It is an array of IOMMUs which during run time gets sorted depending

	 * on its dependency order. After rootfs_initcall is complete

	 * this section can be safely removed.

	 */

	.iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) {

		__iommu_table = .;

		*(.iommu_table)